Time delay relay



June 2, 1964 1'. o. LILLQUIST 3,135,847

TIME DELAY RELAY Filed Sept. 22, 1961 INVENTOR. 73/37? 0 GZZ z/I'sfATTORNEY United States Patent 3,135,847 TIME DELAY RELAY Torsten 0.Liliquist, La Grange, 11]., assignor to General Motors Corporation,Detroit, Mich, a corporation of Delaware Filed Sept. 22, 1961, Ser. No.139,933 6 Claims. (Cl. 200-97) This invention relates to a time delayrelay of the type that provides a predetermined time interval or delaybetween the energization of the relay and the closing or opening of anassociated switch.

In the past, various forms of devices such as springor counterweightlevers have been utilized in time delay relays for the storage of energyfor subsequent utilization in actuating a retarding mechanism thatserves to control the time delay period. When utilizing a spring typedevice, an uncontrollable variable period occurs before the energy beingstored in the spring can commence to operate, resulting in variation ofa timed interval between the opening or closing of the switch contacts.Likewise, problems have occurred with a counterweight lever device inthat the latter usually is composed of a weight threaded on a shaft.This arrangement can cause a variance in the time delay period in thatthe weight may reposition itself along the lever, and thereby fail tomaintain a constant source of energy. Similarly, various devices havebeen provided for delaying or retarding the time involved fordissipating the stored energy. The dash pot is the most common deviceutilized and, for the most part, these devices are found to bemechanically defective when utilized for a sustained period.

The purpose of this invention is to alleviate the defects of theprevious devices by providing a time delay relay having a magneticarrangement for storing energy and for controlling the dissipation ofthis energy during a predetermined time interval. Briefly, the inventioncomprehends a time delay relay wherein a switch is actuated by arotatable cam that is associated with a torque motor for receiving andstoring energy during the rotation of the cam, and with a magnetic brakefor controlling the return movement of the torque motor and the cam;suitable clutch means being provided for engaging and disengaging themagnetic brake with the cam and torque motor.

The above and other features of the invention will be readilyascertainable from the following description of a preferred embodimentmade with reference to the accompanying drawings in which:

FIGURE 1 is an elevation view with parts broken away and in section of atime delay relay incorporating the present invention;

FIGURE 2 is a sectional view taken on lines 22 of FIGURE 1;

FIGURE 3 is a sectional view in an enlarged form taken on lines 3-3 ofFIGURE 1;

FIGURE 4 is an enlarged view with parts broken away of a one-way clutcharrangement employed by the time delay relay of FIGURE 1;

FIGURE 5 is a sectional view taken on lines 5-5 of FIGURE 4;

FIGURE 6 is a sectional view taken on lines 6-6 of FIGURE 4; and

FIGURE 7 is another view of the device shown in FIG- URE 1 with someparts thereof repositioned.

Referring now to the drawings, FIGURE 1 illustrates a time delay deviceor relay including a U-shaped support bracket 12 that is fastened to avertically extending beam 14 by a bolt 16. An electromagnetic device orsolenoid 18 is screwed into the lower portion of the bracket 12 by athreaded portion 29 with a hexagonal nut 22 securely mounting thesolenoid 18 to the bracket 12. For purposes which will hereinafter beexplained, the hexagonal nut 22 may adjustably position the solenoid sothat the latter is movable in a vertical direction with respect to thebracket. The solenoid 18 includes an armature normally biased into adownward position by a spring 24. The upper end of the armature isformed as a rack 26. and as best seen in FIGURE 5, consists of anelongated bar having a plurality of teeth 27 formed on one side thereofwith a tooth free portion disposed below the teeth. The rack teeth 27mate with teeth 29 of a pinion gear 52 that is rotated bythe rack uponenergization of the solenoid.

A torque motor, generally indicated by the numeral 28, is mounted on arotatable shaft 30 that has an adjustable cam 32 fixed thereby by ascrew 34. One end of the shaft 30 is journaled in a ball bearing 31while the other end is associated with a dual one-way clutch arrangementthat will hereinafter be described. As best viewed in FIGURE 2, thetorque motor 28 includes a cylindrical rotor 36 that is magnetized withNorth and South polarities at points diametrically opposite to eachother, and is concentrically located in a ring-type stator 38 that isrigidly connected to the support 12 by a pair of pins 40. As in the caseof the rotor, the stator 38 is magnetized with North and South polarityat points diametrically opposed to each other resulting in anarrangement wherein the unlike poles of the stator and rotor attracteach other and maintain the rotor in the position shown in FIG- URE 2.

Immediately above the cam 32, a switch 42 is fixed to the bracket 12 bya screw 44. An intermediate member 46 is interposed between the cam andthe switch 42 and serves to maintain the latter in an open or closedposition depending upon the position of the cam 32. A stop mem ber 48 inthe form of an upstanding bar is located immediately below the cam 32for limiting the rotary movement of the cam.

As best seen in FIGURES 4 through 6, the shaft 30 has a star wheel orratchet 50 rigidly mounted thereon that forms one part of a one-wayclutch arrangement for permitting drive to be directed from the shaft 30to a retarding mechanism that will hereinafter be described. The piniongear 52 is rotatably positioned on the shaft adjacent the ratchet 50 andis integral with a second star wheel or ratchet 54. The ratchet 54 is aportion of a second clutching mechanism that permits the pinion 52 todirect drive through the shaft 30 to a torque motor 28, and also provideslippage of the pinion 52 through a slipdisc clutch arrangement 56whenever the cam 32 has engaged the stop 48 prior to the full upwardtravel of the rack 26. The slip-disc clutch arrangement includes apivotally mounted pawl 58 with a spring 60 engaging the outer surface ofthe pawl and maintaining the latter in engagement with the teeth of theratchet 54. At this point it can be seen that the ratchet 54, and pawl58 constitute a portion of a clutching arrangement that directs drivefrom the pinion 52 to the shaft 30 upon an upward movement of the rack.As seen in FIGURE 6 a spring 66 biases a pawl 62 into engagement withthe teeth of the ratchet 50 and, as in the aforementioned arrangement, aone-way clutching mechanism is formed by these parts. In this instance,however, clockwise rotation of the shaft 30 as viewed in FIGURE 6,causes the pawl 62 to ride over the ratchet teeth, and drive can only betransmitted through this clutch to a shaft 64 when the shaft 30 rotatesin a counterclockwise direction.

The shaft 64 is rotatably mounted in the support bracket 12 by a ballbearing 68 with a gear 70 fixedly mounted on the end of the shaft. Thegear 70 is engageable with a gear 72 that is fixed to a shaft 74 whichis spaced above the shaft 64 and has one end journaled in a ball bearing76 and the other end rotatably mounted in an enclosure 78. The enclosure78 houses the retarding or brake stator 38 results.

mechanism that includes a cylindrical support member Stl havingarr-opening 82 that is large enough to permit the shaft 74 to extendtherethrough without any interference. The support 8G is fastened to awall 83 and rigidly carries a disc-shaped magnet- 84 that is disposedconcentrically within a ring member 36 made of a soft iron and rigidlymounted to a plate 88. The plate 88, in turn, is mounted in the shaft 74by a frictional connection that permits the plate 88 and associated ringmember 86 to be driven bythe shaft, and, in addition, be movable axiallyalong the shaft so as to vary the magnitude of the magnetic fieldexisting between the ring member and the magnetized disc 84. As bestviewed in FIGURE 3, the ring member 86 circumferentially surrounds thedisc magnet 84 that is similar to the rotor 36 in that it is magnetizedwith North and South polarities at points diametrically opposite to eachother.

Referring now to FIGURE 7, the time delay device of FIGURE 1 is shown,however, in this instance the solenoid 18 is adjusted so that the rack2a is situated in a new lower position with respect to the pinion 52.This adjustment is accomplished by the hexagonal nut 22 and threadedportion 20 of the solenoid 18. This new arrangement of the solenoid andassociated rack 26 brings about a new result in the operation of thetime device which is explained below.

The operation of the present invention is as follows:

Upon energization of the solenoid IS, the armature and the attached rack26 are raised vertically upwardly against the bias of the spring 2Because of the tooth engagement between the rack 26 and the pinion 52,this movement causes a clockwise rotation of the pinion as viewed inFIGURE 5. At the same time the ratchet 54 which is rigid with the pinionengages the pawl 53 to transmit rotational drive to the shaft 39 throughthe disc member 56. Inasmuch as the ratchet wheel 50 is rigid with theshaft 30, a clockwise rotation of this wheel also occurs. However, inthis instance the pawl 62 rides over the ratchet teeth withouttransmitting anydrive to the shaft 64. The rotation of the shaft 36results in a corresponding angular displacement of the attached rotor 36and cam 32 causing the raised position of the cam to release theintermediate member 46 from engagement with switch 42 thereby openingthe switch contacts. A"- suming the rack 26 moves in an upward directionso as to cause a 170 rotation of the pinion 52, a similar angulardisplacement of the rotor with respect to the stationary Due to therotation of the rotor 36, the North and South poles of the rotor arerotated so as to be disposed closer to the respective poles of thestator 38. In other words, the North poles and South poles of both therotor and stator are then located proximate to each other. As is wellknown from the principles of magnetism, like poles tend to repel eachother while unlike poles attract each other. In accordance with thisprinciple the magnetic forces acting between the displaced rotor and thestator exert a returning force on the rotor urging it to return to theoriginal position shown in FIG- URE 2. It should be noted that uponenergization, the solenoid 13 extends the rack in an upward direction beyond the end of the teeth so as to present the tooth free area adjacentthe pinion. Therefore, the rotor and the shaft 30 are free to rotate ina counterclockwise direction under the influence of the magnetic forces.

During the counterclockwise return movement of the rotor, the rigidlyconnected ratchet wheel 5t engages the pawl 62 mounted on the shaft 64and transmits counterclockwise rotation to the shaft 64a The shaft 64,in turn, rotates the' gear 70 and, due to the engagement with the gear72, drives the shaft '74 in a clockwise direction. As aforementioned,the frictional connection between the shaft 74 and the plate 88 servesto rotate the ring as about the periphery of the magnetized disc 84. Themagnetic forces acting between the disc 84 and the ring 86 act as aretarding force or brake for controlling the rotation of the gears 79and 72 and thereby govern the return movement of the torque motor orrotor 36. In this manner, a predetermined time interval elapses beforethe rotor 36 returns from its normal position as shown in FIGURE 2. Whenthe rotor 36 returns to its initial position, the raised portion of cam32 once again engages the intermediate member 46 and closes the contactsof switch 42. This completes the cycle.

The time delay device shown in FIGURE 7 is identical to that shown inFIGURE 1, however, here the solenoid is lowered so that the teeth ofrack 26 do not disengage the pinion 52 when. the solenoid i3 isenergized. Thisis accomplished by loosening the hexagonal nut 22 on thethreaded portion 20 followed by rotating the solenoid about its axis tomove the entire unit to the new position shown in FIGURE 7. Now,energization of the solenoid raises the rack 26, however, due to theengagement of the rack teeth with the pinion, the rack prevents thepinion from moving in a counterclockwise direction. Inasmuch as thepinion is connected to the shaft 30 through the pawl'58, the shaft 3t)is held from counterclockwise rotation until the solenoid 18 isdeenergized. Upon deenergization of the solenoid 18, the rack 2&5returns to its original position, moving in a downward direction andcausing a counterclockwise rotation of the pinion 52 and the ratchetwheel 54-. This latter movement of the pinion has no effect on theassociated parts of the device because as the pinion moves in acounterclockwise direction, the pawl 58 simply rides over the teeth ofthe ratchet 54. Thereupon, the rotor 36 is free to return to itsoriginal position under the control of the magnetic brake as describedabove.

It should be noted that the slip-disc clutch arrangement 56 permits therack 26 to travel the full. extent of the toothed portion thereof in theevent that the solenoid 18 is energized, momentarily de-energized, andimmediately re-energized. This can be understood best by noting thatupon initial energization of the embodiment shown in FIGURE 1, the rackmoves upwardly to a point where the rack teeth 27 clear the pinion teethand the tooth-free portion is adjacent the pinion, as aforementioned.Immediately, the torque motor 23 begins to return to its originalposition under the control of the magnetic brake mechanism. During thereturn movement of the torque motor, a de-energization of the solenoid318 causes a downward movement of the rack without effecting theoperation of the time delay device. However, if the solenoid isimmediately re-energized prior to the full return movement of the .rotor36, the slip-disc clutch arrange ment 56 permits the rack 26 to re-windthe torque motor to the point of cam contact with the stop 43 andthereupon continue its upward movement until all of the teeth 27 areclearof the pinion so that a new full cycle is reinitiated. I t

It is to be understood that the device as described and shown herein isfor the purpose of illustration and that various changes andmodifications may be made without departing from the spirit and scope ofthe invention as set forth in the appended claims.

I claim:

1. A time delay device comprising a support, a switch mounted on saidsupport, a shaft having a magnetic torque motor mounted thereon androtatably carried by said support, said magnetic torque motor comprisinga rotor and a ring stator having opposite polarity at diametricallyopposed points, a switch actuator fixed to said shaft and having a firstposition for closing the switch and a second position for maintainingthe switch open, means for moving the actuator from the first to thesecond position, whereby said rotor is angularly displaced with respectto the stator so as to cause a magnetic attracting force urging saidrotor to its normal position, clutch means, and delay means including amagnetic brake connected with said clutch means for controlling themovement of the actuator from the second to the first position during apredetermined time interval.

2. The device of claim 1 wherein said means comprises an electromagneticdevice having a rack, a pinion mounted on the shaft and engageable, bysaid rack for rotating the shaft a predetermined angular distance. I

3. The device of claim 2 wherein a one-way clutch is associated withsaid pinion for rendering said electromagnetic device effective in onedirection only.

4. The device of claim 3 having means including said electromagneticdevice for adjustably positioning the latter whereby upon energizationof the electromagnet the rack maintains tooth engagement with the pinionand thereby precludes movement of the actuator until deenergized.

5. A time delay relay comprising a support having a I switch mountedtherein, a first shaft rotatably mounted in said support and having aswitch actuator for opening and closing said switch, a magnetic torquemotor associated with said shaft and comprising a rotor fixed to one endof said shaft, a stator circumferentially enclosing said rotor and finedto said support, said rotor and stator being magnetized with North andSouth polarity, a second shaft in axial alignment with said first shaft,a third shaft disposed adjacent said second shaft and in parallelrelationship therewith, gear means connecting said second shaft to saidthird shaft, a stationary magnetized disc, a cylindrical memberadjustably connected to one end of the third shaft and disposed so as tocircumferentially enclose said magnetized disc and rotate thereabout,said disc and said cylindrical member constituting a magnetic brake forcontrolling the speed of clutch means adapted to receive the returndrive fromv said rotor through said first shaft and transmit said driveto'said second shaft under the control of the magnetic brake during apredetermined time interval.

6. The device of claim 5 wherein said switch actuator includes a cam, astop incorporated with said device to limit the angular movement of saidcam, said electromagnet means having a rack, a pinion mounted on saidfirst shaft and engageable by the rack, a slip-disc clutch arrangementassociated with the pinion and adapted to provide slippage between saidpinion and said shaft whenever said electromagnet is energized and thecam engages said stop prior to the full travel of the rack.

References Cited in the file of this patent.

UNITED STATES PATENTS 1,027,440 Schley May 28, 1912 1,499,178 McLainJune 24, 1924 2,319,279 Watkins May 18, 1943 2,598,748 Alles June 3,1952 2,636,095 Schulte Apr. 21, 1953 2,945,932 Nemeth July 19, 19602,976,379 Rhodes Mar. 21, 1961

1. A TIME DELAY DEVICE COMPRISING A SUPPORT, A SWITCH MOUNTED ON SAIDSUPPORT, A SHAFT HAVING A MAGNETIC TORQUE MOTOR MOUNTED THEREON ANDROTATABLY CARRIED BY SAID SUPPORT, SAID MAGNETIC TORQUE MOTOR COMPRISINGA ROTOR AND A RING STATOR HAVING OPPOSITE POLARITY AT DIAMETRICALLYOPPOSED POINTS, A SWITCH ACTUATOR FIXED TO SAID SHAFT AND HAVING A FIRSTPOSITION FOR CLOSING THE SWITCH AND A SECOND POSITION FOR MAINTAININGTHE SWITCH OPEN, MEANS FOR MOVING THE ACTUATOR FROM THE FIRST TO THESECOND POSITION, WHEREBY SAID ROTOR IS ANGULARLY DISPLACED WITH RESPECTTO THE STATOR SO AS TO CAUSE A MAGNETIC ATTRACTING FORCE URGING SAIDROTOR TO ITS NORMAL POSITION, CLUTCH MEANS, AND DELAY MEANS INCLUDING AMAGNETIC BRAKE CONNECTED WITH SAID CLUTCH MEANS FOR CONTROLLING THEMOVEMENT OF THE ACTUATOR FROM THE SECOND TO THE FIRST POSITION DURING APREDETERMINED TIME INTERVAL.